1. Field of the Invention
This invention relates to a portable circular hand held power saw base plate. This base plate has the capability of engaging a system to preform a precision perpendicular cut to the longitudinal axis of the material being cut.
This base plate is not an add on saw guide to a hand help circular power saw, but rather, a new type of base plate that can be manufactured with the saw or as a retro--fit precision saw base replacement for existing circular saws. This base plate can be used like any presently manufactured circular saw base plate but has the capability of engaging the precision cut mechanism.
2. Description of the Prior Art
A review of the art in the field reveals a number of devices designed to guide a circular saw blade perpendicularly across a longitudinal axis. Examples include:
U.S. Pat. No. 4,777,726 issued to randy flowers which describes a guide for portable hand help power circular saws. The primary drawbacks to this invention are the limitation on the width of the material being cut when the guide is in the operating position. From the vertical center axis of the saw blade to the stop positions of the saw guide there is a very limited space for cutting the desired product. Also the coil springs used for resistance to the forward movement of the saw itself, and for the return of the slide plate, are a poor choice of springs as this type of spring offers varying degrees of resistance and a varying degree of force for the slide plate return. PA1 U.S. Pat. No. 4,602,435 issued to Jim Z. Nishioka which describes an aligning mechanism for power hand saws. The primary drawbacks to this invention are the use of a coil spring, which once again, offers varying degrees of resistance and a varying degree of force for the aligning device return, also the aligning device is to the far left of the main force of the forward movement of the saw, thus, this is awkward to hold without getting a pivotal action against the aligning device, which would mis-align a true perpendicular cut. PA1 U.S. Pat. No. 5,279,037 issued to Alfred R. Leatherman which describes a guide for a portable sae. This invention is limited to sheet material and longitudinal cuts as the trailing pin described would not engage normal widths of material before they are already cut.
U.S. Pat. No. 4,619,170 issued to Peter Maier which describes a guide for a hand power tool. The primary draeback for this device id than it requires the clamping of an external guide strip to the work to be cut and an attachment affixed to the saw base to be guided along the strip.
A review of the prior art reveals that the previous inventions are very limited in use and scope. That is, they are limited in the width of the product to be cut, or not refined in design by the type of springs used or require clamping an external guide on the work to be cut.